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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

31727 results found.

  1. GRB 231104A: Swift-BAT refined analysis
  2. Fermi GRB 231106A: Global MASTER-Net observations report
  3. GRB 231104A: Wendelstein Optical/Infrared Observations
  4. GRB 231104A: NuSTAR Observation of the prompt emission
  5. GRB 231104A: 3.6m DOT optical upper limit
  6. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  7. Fermi-LAT gamma-ray observations of IceCube-231103A
  8. GRB 231104A: NOT upper limit
  9. GRB 231104A: Fermi GBM Observation
  10. Fermi GRB 231103A: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S231104ac: Updated Sky localization
  12. GRB 231104A: AKO Upper Limit
  13. GRB 231104A: AstroSat CZTI detection
  14. GRB 231104A: Fermi-LAT detection
  15. LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
  16. GRB 231104A: Swift/UVOT Upper Limits
  17. GRB231104A: LCOGT Optical Upper Limits
  18. Fermi-LAT gamma-ray observations of IceCube-231027A
  19. LIGO/Virgo/KAGRA S231102w: Updated Sky localization
  20. GRB 231101A: Glowbug gamma-ray detection
  21. GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
  22. LIGO/Virgo/KAGRA S231102w: Identification of a GW compact binary merger candidate
  23. New Swift-BAT/GUANO and IceCube Notices Available via GCN Kafka
  24. GRB 231030B: GRBAlpha detection
  25. GRB 231030B: Fermi GBM Detection
  26. GRB 231030B: AstroSat CZTI detection
  27. Fermi GRB 231030B: Global MASTER-Net observations report
  28. IPN triangulation of GRB 231020A
  29. GRB 231028A: Swift-BAT refined analysis
  30. IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
  31. GRB 231024A: AKO Optical Counterpart Candidate
  32. GRB 231028A: CALET Gamma-Ray Burst Monitor detection
  33. Fermi GRB 231030A: Global MASTER-Net observations report
  34. LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate
  35. GRID detection of GRB 231020A
  36. GRB 231028A: AstroSat CZTI detection
  37. GRB 231028A: Glowbug gamma-ray detection
  38. GRB 231028A: Fermi GBM Detection
  39. Swift GRB 231028A: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S231028bg: Updated Sky localization
  41. LIGO/Virgo/KAGRA S231028bg: Identification of a GW compact binary merger candidate
  42. GRB 231028A: Swift detection of a burst
  43. GRB 231019A: Glowbug gamma-ray detection
  44. IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
  45. GRB 231025A: Fermi GBM Observation
  46. GRB 231024A: Fermi GBM Observation
  47. GRB 231025A: Swift/BAT-GUANO detection of a likely short burst
  48. GRB 231024A: X-shooter spectroscopy of AT2023vuc/GOTO23baj reveals a young supernova with flash ionisation features
  49. GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  50. GRB 231020A: AstroSat CZTI detection
  51. GRB 231020B: AstroSat CZTI detection
  52. GRB 231024A: GOTO optical counterpart candidate
  53. The photometry of the transient in Messier 31 field: GMG observation
  54. GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  55. LIGO/Virgo/KAGRA S231020bw: Updated Sky localization
  56. GRB 231020A: Fermi GBM Detection
  57. GRID detection of GRB 231004A
  58. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  59. GRB 231019A: VZLUSAT-2 detection
  60. GRB 231018A: VZLUSAT-2 detection
  61. LIGO/Virgo/KAGRA S231020ba: Updated Sky localization and EM Bright Classification
  62. LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations
  63. GRB 231015A: NuSTAR Detection of Prompt Emission
  64. Fermi GRB 231020A: Global MASTER-Net observations report
  65. LIGO/Virgo/KAGRA S231020bw: Identification of a GW compact binary merger candidate
  66. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  67. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  68. GRB 231017A: 1.3m DFOT Optical upper limit
  69. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  70. IceCube-231004A: Upper limits from Fermi-GBM Observations
  71. GRB 231018A: GRBAlpha detection
  72. GRB 231018A: CALET Gamma-Ray Burst Monitor detection
  73. Fermi GRB 231019A: Global MASTER-Net observations report
  74. GRB 231018A: Glowbug gamma-ray detection
  75. Konus-Wind detection of GRB 231018A
  76. IPN triangulation of GRB 231018A
  77. GRB 231017A: Swift/UVOT Upper Limit
  78. GRB 230911C: ATCA detection of possible radio counterpart
  79. GRB 231017A: GOTO optical upper limits
  80. GRB 231017A: JinShan optical upper limit
  81. GRB 231018A: GROWTH-India Follow-Up of a Fermi Long GRB
  82. IC231004A: Classification of AT2023uqf/ZTF23abidzvf as a rapidly-evolving supernova with CSM interaction
  83. GRB 231017A: Las Cumbres optical upper limit
  84. GRB 231015A: Glowbug gamma-ray detection
  85. GRB 231017A: LCOGT Optical Upper Limits
  86. GRB231017A: GROWTH-India upper limits on the optical afterglow
  87. GRB 231015A: AstroSat CZTI detection
  88. GRB 231018A: Fermi GBM Detection
  89. GRB 231017A: Fermi GBM Detection
  90. GRB 231017A: Swift-XRT observations
  91. GRB 231012B may not be a GRB
  92. GRB 231017A: Swift ToO observations
  93. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  94. Fermi-LAT gamma-ray observations of IceCube-231014A
  95. IceCube-231014A: Upper limits from a search for additional neutrino events in IceCube
  96. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  97. Correction in GCN 34814: GRB 231012B (not GRB 231012A)
  98. GRB 231004A: Glowbug gamma-ray detection
  99. LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
  100. IceCube-231004A: One Candidate Counterpart from the Zwicky Transient Facility

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